Historically, elastic bandages have been made in a woven structure, using narrow or ribbon looms, wherein the retractive and supportive power has been supplied by special warp yarns. Early bandages employed overtwisted cotton warp yarns, as shown in the Teufel 1908 U.S. Pat. No. 889,827, or in the Klein 1932 U.S. Pat. No. 1,875,740.
The use of cotton warp yarns has been displaced to a considerable extent by the use of elastomeric warp yarns, initially of extruded or cut rubber, more recently of other elastomeric manmade polymers. Such elastomeric warp yarns are usually wrapped with a layer of non-elastomeric filaments.
Such bandages, although effective in use, suffer from the disadvantage of being relatively expensive. They are produced singly on a narrow loom, utilizing expensive wrapped elastomeric yarns, at comparatively slow production rates inherent in the weaving process.
In an attempt to circumvent the limitations of the weaving process, it has been proposed to produce elastic bandages in a knitted structure, as in U.S. Pat. No. 3,965,703, to Barnhardt.
The knit structures thus far, however, still employ elastomeric yarns as part of the warp structure, and customarily employ very heavy filling yarns to prevent necking-in of the bandage when stretched. They are relatively heavy in weight, averaging 6 to 12 oz. per square yard (204 to 408 grams per square meter), and due to their compact structure they become hot and uncomfortable to wear. Also, when applied to a limb or other body member they must be secured in place in the outer wrap by means of some sort of fastening, such as toothed metal clips. As the bandage is worn, the layers of the bandage tend to slip and slide past each other, leading to the undesirable alternatives of frequent removal and rewinding or else winding the bandage with an uncomfortable degree of tension.
It is with improvements in the production of bandages of this type that the present invention is concerned.